Particle foam component having a textured surface and method and mold for the manufacture thereof

ABSTRACT

A mold for forming an element molded from a particle foam, including for example expanded polypropylene foam, includes at least one visible exterior surface defined by the particle foam. The visible exterior surface is textured having a roughness depth of less than or equal to 1.00 mm and a plurality of vent interfaces each having a maximum width of less than or equal to 0.4 mm. Methods of molding the element, together with a mold and a method of making the mold, are also provided.

This application is a continuation of U.S. patent application Ser. No.14/211,029, filed Mar. 14, 2014, which claims the benefit of U.S.Provisional Application No. 61/791,781, filed Mar. 15, 2013, the entiredisclosures of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates generally to a particle foam component,including for example an expanded polypropylene (EPP) foam component,such as a partition, having a textured class-A surface that is visuallypleasing, and to various methods and molds for the manufacture thereof.

BACKGROUND

Various reconfigurable partition and workspace systems are well known.Typically, such systems define predetermined, fixed workspace footprintsthat are not variable, but rather are defined by the length ofindividual wall units incorporated into the system. As such, these typesof systems are not easily reconfigurable to accommodate different,individual spatial and functional needs of the users. In addition, suchsystems are often closed or provide relative high barriers, which mayinhibit collaboration and communication between adjacent coworkers.

In addition, conventional systems typically are one-sided, with storage,worksurfaces and/or other accessories mounted and/or made accessiblefrom only one side of wall unit. As such, the systems make lack theability to promote team building and collaboration across the partition.Moreover, such systems typically require extensive assembly anddisassembly time and are relatively heavy, thereby limiting theportability and reconfigurability of the system. Furthermore, suchsystems may require a large variety of individual parts and connectors,which may be easily misplaced.

Separate and apart from known partition systems, it is known to moldcomponents from EPP. Typically, such components may not have a surfacefinish suitable for consumer, such as in the office, home or vehicleenvironment, thereby requiring additional treatment or covering of sucha surface. Moreover, it may be difficult to achieve a suitableappearance on more than one side of a component or on relatively largecomponents, due to various tooling limitations.

SUMMARY

Briefly stated, in one aspect, one embodiment of a molded componentincludes an element molded from a particle foam, including for exampleand without limitation expanded polypropylene foam. The element includesat least one visible exterior surface defined by the particle foam. Thevisible exterior surface is textured having a roughness depth of lessthan or equal to 1.0 mm, and in one embodiment less than or equal to 0.5mm, and a plurality of vent interfaces each having a maximum width ofless than or equal to 0.4 mm. In one embodiment, the plurality of ventinterfaces are distributed with a density of one vent interface per 100mm2 of surface area or less.

In another aspect, one embodiment of a method of molding a componentincludes introducing beads of a particle foam, including for example andwithout limitation expanded polypropylene foam, into a mold interior,wherein the mold includes at least one textured molding surface definingat least in part the mold interior. The molding surface has a roughnessdepth of less than or equal to 0.5 mm and a plurality of vents eachhaving a maximum width of less than or equal to 0.4 mm. The methodfurther includes introducing steam into the mold interior through theplurality of vents for a predetermined period of time, fusing the beadsof particle foam with the steam and thereby forming a molded element,and removing the molded element from the mold.

In yet another aspect, a mold for molding particle foam, including forexample and without limitation expanded polypropylene foam, includes atleast one mold component defining at least in part a mold interior. Themold component includes at least one textured molding surface definingat least in part the mold interior, wherein the textured molding surfacehas a roughness depth of less than or equal to 0.5 mm and a plurality ofvents each having a maximum width of less than or equal to 0.4 mm.

In yet another aspect, one embodiment of a method of making a mold formolding a particle foam, including for example and without limitationexpanded polypropylene foam, includes providing at least one moldcomponent defining at least one molding surface, and treating themolding surface such that the molding surface includes a roughness depthof less than or equal to 0.5 mm. In one embodiment, the treating of themolding surface includes etching the molding surface. In one embodiment,the method further includes drilling vents through the mold component.The vents communicate with the molding surface. The vents have a maximumwidth of less than or equal to 0.4 mm.

The various aspects and embodiments provide significant advantages overother partition and workspace systems. For example and withoutlimitation, the molded component has a premium class-A finish suitablefor direct interface with end users. In addition, the component may bemade relatively large, and be provided with a premium finish on morethan one side.

The present embodiments of the invention, together with further objectsand advantages, will be best understood by reference to the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a partition system.

FIG. 2 is a perspective view of a partition system.

FIG. 3 is a cross-sectional view of a mold.

FIG. 4 is a perspective view of a mold element.

FIG. 5 is view of two film etching finishes.

FIGS. 6A-6D show various vent hole arrangements.

FIG. 7 is a schematic showing the process of making a mold component.

FIGS. 8A-F show different phases of the ejection of a mold componentfrom a mold.

FIG. 9 is a side schematic view of one embodiment of mold.

FIGS. 10A-C show different phases of the molding process using the moldshown in FIG. 9.

FIG. 11 is a flow diagram of the molding process.

FIGS. 12A-L are schematic diagrams of the mold assembly corresponding tothe molding steps of FIG. 11.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The terms “longitudinal” and “axial” as used herein relates to a lengthor lengthwise direction, including for example a lengthwise direction ofa partition or mold component, and may include both a horizontal andvertical direction notwithstanding that those directions aresubstantially perpendicular respectively. The term “lateral” andvariations thereof refer to a sideways direction. The terms “top,”“upper,” “bottom” and “lower” are intended to indicate directions whenviewing the partition when positioned for use. It should be understoodthat the term “plurality,” as used herein, means two or more. The term“coupled” means connected to or engaged with, whether directly orindirectly, for example with an intervening member, and does not requirethe engagement to be fixed or permanent, although it may be fixed orpermanent. The term “transverse” means extending across an axis,including without limitation substantially perpendicular to an axis. Itshould be understood that the use of numerical terms “first,” “second,”“third,” etc., as used herein does not refer to any particular sequenceor order of components; for example “first” and “second” portions mayrefer to any sequence of such portions, and is not limited to the firstand second portions of a particular configuration unless otherwisespecified. The term “plurality” means two or more, or more than one.

Molded Component

Referring to FIGS. 1 and 2, a partition system 2 is configured with aplurality of wall elements 4, 6, 8, 10, 12 which may be arrangedend-to-end in various configurations. The wall elements may be curved orlinear elements 4, 6 or combinations thereof, and may include varioustransition and corner elements 6, 8, 10, 12. In one embodiment, the wallelements 4, 6, 8, 10, 12 are configured as stepped element, whichdefines a plurality of walls 14, 16, 18, 20 arranged at differentheights, and a plurality of channels 22, 24, 26 arranged at differentheights. Each of the walls 14, 16, 18, 20 has an opposite side wallshaving a width (WW) and an upper support surface. Likewise, each of thechannels 22, 24, 26 has a bottom and opposite side walls defining awidth (CW) of the channel. Pairs of walls 14, 16, 18, 20 define thechannels 22, 24, 26 therebetween, with the sidewalls of spaced apartwalls corresponding to the sidewalls of the channel formed therebetween.In one embodiment, the wall elements are configured with four walls andthree channels, although it should be understood that more or less wallsand channels may be used. In various embodiments, the heights HW1, HW2,HW3, and HW4 of the walls 20, 18, 16, 14 are 42 inches, 35.5 inches,29.00 inches and 22.5 inches respectively in one embodiment, and 41.625inches, 35.312 inches, 29.00 inches and 22.69 inches respectively inanother embodiment, while the height of the bottom of the channels HC 1,HC2 and HC3 are 31.16 inches, 24.85 inches and 18.54 inchesrespectively, although other heights may be suitable. The walls, whenconfigured with a worksurface component 50 secured thereto, provide aworksurface at a counter height, a kitchen counter height, a work tableheight and a continental table height respectively. The depth of thechannels (height of front wall to bottom of channel) may be calculated,and is about 4.5 inches in one embodiment. In addition, the walls mayhave linear sides as shown, or may be tapered. The width (CW) of thechannels 22, 24, 26 is 2.00 inches, and preferably between 1 and 10inches, while the width (WW) of the walls 14, 16, 18, 20 is also 2.00inches, and preferably between 1 and 10 inches. It should be understoodthat other heights and widths may be suitable. Preferably, the widths ofthe walls are the same such that they are suited to support similarcomponents, but varying widths may be employed. Likewise, the widths ofthe channels are the same to support similarly shaped and dimensionedcomponents, but the widths may vary as deemed appropriate.

The wall elements 4, 6, 8, 10 have opposite end surfaces 28, 30, 32, 34,36, 38, 40, 42 defining a length of the respective wall elements, andwhich are abutted during assembly. Each wall element, otherwise referredto as a furniture “base,” may be made of a particle foam, which includesfor example and without limitation EPP foam. Other particle foams may bemade from other materials, including for example various com starches.The wall elements may be configured with an interior space 44 formedtherein, for example along a bottom of the wall element as shown in FIG.3. Referring to FIG. 1, adjacent wall elements may be joined by one ormore connector elements 46, 48. The connector elements are moldedplastic in one embodiment, and include a pair of downwardly extendingprojections 52 that are received in openings 56 formed in the adjacentwall elements. The connector further includes an upwardly extendinggrippable portion 58, or handle, which may be grasped by a user tofacilitate installation and extraction of the connector. The connectorfurther includes a septum 54 extending downwardly between theprojections. The septum helps to locate the connector relative to thewall elements. The septum keeps the connector from twisting relative tothe wall elements. The septum may be omitted in various embodiments. Inone embodiment, a pair of connectors 48 joins adjacent wall elements inthe uppermost and lowermost channels, although it should be understoodthat a connector may also be installed in an intermediate, or middlechannel. A bottom connector 46 may include a pair of upwardly extendingposts that engage openings in adjacent wall elements.

In one embodiment, the geometrical shape of each wall element 4, 6, 8,10, 12 is defined by a core 68 composed of a solid material as shown inFIG. 3. In one embodiment, the core material is homogenous, meaning thecore is made of the same material, from one side of the element to theother, and defines for example exterior, visible surfaces of the sidewalls 14, 16, 18, 20 and channels and the end surfaces 28, 30, 32, 34,36, 38, 40, 42 of the wall elements, free of any further covering orlayer of material. In one embodiment, the upper exterior surfaces, e.g.,the tops of all the wall elements and bottoms of the channels, and lowerexterior surface 70, i.e. bottom of the wall elements, are likewisedefined by the same core material. In some embodiments, the entirethickness, width and/or height of the core 68 may be configured of asolid material. In other embodiments, various voids 44 may be formedinternally, for example to provide for attachment of various accessorycomponents, or in order to reduce the overall weight of the element. Bymeans of such a formation of the individual wall elements to be in onepiece, and one homogenous material, the wall elements do not have to beassembled from individual components in a laborious and time-consumingmanner.

It should be understood that in other embodiments, the exterior surfaceof the core 68 may be covered, for example by the application of acoating. A finished wall element of this type then consists of a coredefining the geometrical shape and of a shell by means of which the wallelement can be matched in the composition of the surface thereof and/orthe appearance thereof to the individual requirements.

In one embodiment, the core 68 is made of a rigid foam material. Forexample, in one embodiment, the core is made an expandable polystyrene(EPS) which has in particular a volume weight of approximately 20 kg/mto 70 kg/m and in particular approximately 40 kg/m. In anotherembodiment, the solid core 68 material is formed from a particle foam,and in particular an expanded polypropylene (EPP) foam which has avolume weight of approximately 20 kg/m to 70 kg/m and in particularapproximately 40 kg/m. In comparison to wall elements produced, forexample, from wooden panels, the individual wall elements have a lowweight which simplifies in particular transportation, locally on site,or globally from the manufacturing facility. Furthermore, by means ofthe use of materials of this type, the wall elements haveheat-insulating and sound absorbing properties and therefore permiteffective protection of the delimited work place from drafts and sound.In the case of expanded materials, the wall elements can simply beadapted to various requirements, such as, for example, stability andloadbearing capacity, by changing the volume weight.

The EPP foam is formed from polypropylene beads or pearls that are fusedby steam during the molding process. In one embodiment, the EPP beadshave a bulk density (measured as a loose fill) of about 45 g/l. Duringthe molding process, the material will mold to about 60 g/l. The beadhas a diameter of about 3.0 mm. Suitable beads may have a diameterbetween about 2.0 mm and about 5.0 mm. Suitable beads may have a beadbulk density of between about 20 g/l to about 90 g/l. To achieve aclass-A appearance, the exterior surface must mask or disguise both thepearl structure of the EPP beads and also the vent interfaceings thatare left by vent holes 82 in a molding tool 80, shown in FIGS. 3-6D. Asmentioned, the visible exterior surfaces of the wall elements, and inparticular the core, are defined as the outermost surfaces that arevisible to a user.

In one embodiment, the visible exterior surfaces are formed by an EPPfoam having a textured appearance with a matte finish. In oneembodiment, the textured surface is a crepe 300-0 texture. In anexemplary embodiment, the exterior surface has a nominal roughness depthof less than or equal to 0.5 mm and a plurality of vent interfaces eachhaving a maximum width of less than or equal to 0.4 mm. Due to the sizeand interfacing of the EPP pearls, the overall surface may have variousgaps, with a maximum depth from peak to valley being about 1.0 mm. Theterm “vent interface” refers to the mark made on the visible exteriorsurface by the vent holes 82 from the mold. The vent interfaces 86 aregenerally not visible to the naked eye of the user, although present onthe exterior surface, and are therefore ref erred to generally in thedrawings as being distributed on the exterior surface of the wallelements. In various embodiments, the roughness depth of the exteriorsurface is less than or equal to 0.4 mm. In various embodiments, thevent interfaces 86 are circular and have a diameter of less than orequal to 0.4 mm. It should be understood, however, that the ventinterfaces, and corresponding vent holes, may be configured in othershapes, including various elliptical, obround, and polygonal shapes, alllimited by a maximum dimension, defined as a width of the opening.

Due to the combination of the textured finish of the visible exteriorsurface and the size of the vent interfaces, the exterior surfacedisguises both the interfaces and the pearl structure of the EPP foam,thereby providing a class-A surface. In essence, a “crepe” finishresembles the result of a natural process such as corrosion, such thatthe surface does not appear predetermined, but rather is a randomtexture without repeats within a certain range of roughness or depth.The roughness (refers to size/resolution) and the depth match the EPPbead size in away and therefore disguises them within the predeterminedfinish. The texture disguises the beads (reproduction of texture depthand geometry) and leads to a matte finish (reproduction of every littlepeak which refracts the light). As explained below, a combination of twoetched textures, one on top of the other, enlarges/increases theresolution of the texture. A matte finish results from the resolution(amount per area) of peaks which refract light. The more peaks that arepresent within the texture provide a better matte finish.

In one embodiment, the plurality of vent interfaces 86 are distributedwith a density of one vent interface 86 per 100 mm2 of surface area orless, as shown in FIG. 6D. Also in one embodiment, the expandedpolypropylene foam is formed from polypropylene beads having a pearlsize of less than or equal to 5.00 mm, and preferably about 3.00 mm.

As discussed above, the visible exterior surface having a class-A finishmay be formed as only one of the surfaces of the wall elements, or maybe formed as a pair of opposite visible side exterior surfaces, forexample the opposite side surfaces. The wall elements may be furtherformed with class-A visible surfaces on the upper and lower visibleexterior surface, and/or also on the end surfaces. While the moldedelement has been disclosed as a partition wall, it should be understoodthat other molded components, including various automotive components,other furniture elements such as a bench or chair, electronic housings,home and office devices, luggage and various storage devices, and anyother component capable of being made of EPP may be formed with such aclass-A visible exterior surface.

As shown in FIG. 1, the partition wall element may be configured with anin-molded accessory interface 90, such as a metal base or stanchionreceiving tube.

Mold

Referring to FIGS. 3, 4 and 8A-F, a mold 100 for molding particle foam,including expanded polypropylene foam, includes at least one moldcomponent 102, 112, 114, 116, 202, 204 defining at least in part a moldinterior. The mold component includes at least one textured moldingsurface 104 defining at least in part the mold interior 106. In oneembodiment, the textured molding surface 104 has a roughness depth ofless than or equal to 0.5 mm and a plurality of vents 82, otherwisereferred to as vent holes, each having a maximum width of less than orequal to 0.4 mm. As noted above, the vents 82 may be circular, having adiameter of 0.4 mm, or may be otherwise shaped. In one embodiment, theroughness depth may be less than or equal to 0.4 mm. The plurality ofvents 82 are distributed with a density of one vent per 100 mm2 ofsurface area or less as shown in FIG. 6B-D. The texture of the moldinterior may be configured with a “crepe” finish. A far side of the venthole is formed as a passageway 86 with a tapered end portion feeding thevents. The passageway 86 having a diameter ranging from 4 mm, to 4.8 mmto 6 mm, as shown in FIGS. 6B-6D. In another embodiment, shown in FIG.6A, a plurality of vents 82, shown as three, are distributed in each 100mm2 of surface area. In this embodiment, a single passageway 86, havingan exemplary diameter of 8 mm, feeds the plurality of vents 82. Thepassageway in this embodiment is not tapered adjacent the vents.

In one embodiment, the mold includes a pair of opposing textured sidemolding surfaces 104, 118 defining at least in part the mold interiorthere between, and may further include an upper and lower texturedmolding surfaces 108, 110 and opposite end textured molding surfaces201, 203 further defining said mold interior 106. In this way, theentirety of the molded component, i.e., the core 68, may be providedwith a class-A exterior surface. To accommodate large components, forexample and without limitation the disclosed wall elements, the moldinterior 106 may be configured with a volume of 1800 mm×1240 mm×1000 mm,or less, including a reduction in any of the dimensional parameters. Inone embodiment, the mold interior defines an exterior shape of apartition wall, although it should be understood that the mold interiormay define any type of molded component suitably made of EPP or otherparticle foam.

As shown in FIGS. 3, 8A-F, 9 and 10A-C, one embodiment of the moldincludes three pairs of mold components, including a pair of side moldcomponents 102, 112, upper and lower mold components 114, 116, and apair of end mold components 202, 204. The mold components 102, 112, 114,116, 202, 204 are moved together to define the mold interior 106. Themold components each include a mold plate 120, 122, 124, 126 definingthe textured molding surface. The mold plates may be reinforced with abacking structure 128, such as ribs or bars due to the relatively largesize of the molding surfaces. Each mold plate is configured with ventholes 82 having the size and density referred to above. The placement ofthe vent holes 82 may be random, may be configured in an array, or maybe positioned so as to be collocated with a valley, or depression in thetextured mold surface. The vent holes include a back side inletpassageway 86 as explained above. As described, an end portion of theinlet passageway tapers to the vent hole.

One or both of the upper and lower mold components 114, 116 are movedtoward and away from each other with actuators 130, 132, shown forexample and without limitation as hydraulic or pneumatic cylinders.Likewise, one or both of the opposite side mold components 112, 102 maybe moved toward and away from each other with actuators 134, 136. One orboth of the end mold components 202, 204 also are moveable toward andaway from each other.

An EPP bead supply line 138 communicates with the mold interior andfills the mold interior with EPP beads. Each mold plate communicateswith a steam supply, with steam being supplied to the mold interiorthrough the vent holes 82. In one embodiment, the cavity is filled fromthe top which may correspond to the bottom of the molded component.Three steam circuits are provided with this mold, as further explainedbelow.

Method of making a Mold for Molding an EPP Component

Referring to FIGS. 3-7, a method of making a mold for molding a particlefoam, including expanded polypropylene foam, includes providing at leastone mold component 102 defining at least one molding surface. In oneembodiment, a pair of mold components define opposite, facing moldingsurfaces. In yet another embodiment, the mold components define side,upper and lower, and opposite end mold surfaces. It should be understoodthat the terms end, side, upper, top, bottom, and lower do notnecessarily refer to planar or linear surfaces, but rather generaldirections or orientation, such that both a cubic and a sphericalstructure could have opposite sides, and upper and lower surfaces.

The mold surfaces 104 are treated such that the molding surface have aroughness depth of less than or equal to 0.5 mm, and may be less than orequal to 0.4 mm. In one embodiment, the molding surface is etched. Thetreating may include etching the molding surface a first time 120 with afilm (see FIG. 5) and etching the molding surface a second time 122 withan etching fluid or another film. The etching may include laser etchingor engraving the surface. The treating may further include sand-blasting124 the molding surface after etching the molding surface the secondtime. The etching and sandblasting, alone or in combination, achieve thedesired surface roughness and texture, for example a crepe finish.

The method further includes drilling vent holes 126 through the moldcomponent 102, e.g., a mold plate, with the vents communicating with themolding surface. In one embodiment, the vent holes have a maximum widthof less than or equal to 0.4 mm. The vent holes 82 may be drilled withconventional machining or by laser drilling. The holes are drilled bydistributing the vent holes in the mold component with a density of onevent hole per 100 mm² of surface area of the mold surface or less.

In various embodiments, the molding surface 102 or surfaces defines atleast in part a mold interior 106. As noted, the mold interior may havea volume of 1800 mm×1240 mm×1000 mm. Of course, the mold interior mayhave lesser dimensions in each direction. In one embodiment, the moldingsurface or surfaces define at least in part a mold interior defining anexterior shape of a partition wall.

Method of making a Molded Particle Foam Component

Referring to FIGS. 3 and 8A-12L, a method of molding a molded particlefoam component, including an EPP component, includes introducing beadsof the particle foam, such as polypropylene foam 150 into a moldinterior 168. The beads may have a bulk density (measured as a loosefill) of about 45 g/l. During the molding process, the material willmold to about 60 g/l. The bead has a diameter of about 3.0 mm. Suitablebeads may have a diameter between about 2.0 mm and about 5.0 mm.Suitable beads may have a bead bulk density of between about 20 g/l toabout 90 g/l. The mold has at least one textured molding surface 104,118, 108, 110 defining at least in part the mold interior. The moldingsurfaces have a roughness depth of less than or equal to 0.5 mm, and inone embodiment, a roughness depth of less than or equal to 0.4 mm.

A plurality of vents 82 each having a maximum width of less than orequal to 0.4 mm communicate with the interior molding surfaces 104, 108,110,118, 201, 203. In one embodiment, the plurality of vents, andcorresponding interfaces 86 are distributed with a density of one ventor vent interface per 100 mm2 of surface area or less.

In a first step of the process (FIG. 12A), the mold components 102, 112,114, 116, 202, 204 are moved together to define the mold interior 106.Next (FIG. 12B), the supply 604 of beads are pre-pressurized in acontainer 602, for example at a pressure of about 3.9 bar, or 390 kPa.In other embodiments, the pressure may range from about 2 bar to about4.5 bar. In one embodiment, the initial density if about 42 g/l (1 pa, 2bar), with the density being about 57 g/l at 3.5 bar. In otherembodiments, suitable bead bulk densities are between about 20 g/l toabout 90 g/l. The chest 604 is back-pressurized to about 3.5 bar (350kPa). In other embodiments, the pressure may range from about 1.5 bar toabout 4.5 bar. Next (FIG. 12C), the beads are allowed to flow into theinterior 106, with a pressure differential of about 0.4 bar between thecontainer and the mold interior 106. In other embodiments, the pressuredifferential may range from about 0.1 bar to about 1.5 bar. This processmay be accomplished in about 35-40 s. In the next step (FIG. 12D), steamis introduced through lines 608, 610 feeding opposite sides of thechamber 604, with the steam being pushed from the top to bottom drainvalves 612, 614 to move air from both sides of the steam chest 604,taking about 4s. Referring to FIGS. 12E and 10A, a first cross steamflow through the mold interior is performed to ensure inner fusion ofthe beads, with an elapsed time of about 4-5 s. The flow comes fromsupply line 608 at a pressure of between about 0 and 3 bar. As shown,the flow exits through a first drain valve 614. Referring to FIGS. 12Fand 10B, a second cross steam flow in an opposite direction through themold interior is performed, again with an elapsed time of about 4-5 s.The flow comes from supply line 610 and exits through an opposite seconddrain valve 612, again at a pressure of about 0 to 3 bar. Referring toFIG. 10C, an alternative third cross steam flow may also be performed.Referring to FIG. 12G, an autoclave step is performed, with the drainvalves 612, 614 closed and steam supplied by lines 608, 610 at apressure of about 3.5 bar. In other embodiments, the pressure may rangefrom about 2 bar to about 4 bar. The temperature in the cavity remainselevated, for example at about 147 degrees C. In other embodiments, thetemperature may range from about 100 degrees C. to 200 degrees C. Thevalves remain closed for about 80 s, although other embodiments includeperiods of between about 10 s and about 120 s. During this period, thepressure is released from the inside of the foam. In the next step (FIG.12H), the drain valves 612, 614 remain closed, with the steam pressureslowly diminishing due to condensation, with the foam relaxing. In acondensation phase, lasting about 5 s in one embodiment, cooling waterat a pressure of about 4-6 bar and 30 degrees C. is introduced throughlines 616, 618 with the drain valves 612, 614 remaining closed to reducethe steam pressure through condensation. Referring to FIG. 12J, intervalcooling is then performed for 120 s (range of from about 10 s to 200 s),with intervals of 3 s of water, 5 s after cooling and 5 s pause, each ofwhich intervals may be 1-10 s in various embodiments. During this phase,water is supplied through lines 616, 618, with the drain valves 612, 614being opened. Referring to FIG. 12K, additional air after cooling isperformed for a period of about 15 s. A final passive phase of foampressure reduction is undertaken as shown in FIG. 12L, lasting about 100s.

Referring to FIGS. 8A-F, the molded component is then ejected. In oneembodiment, the end mold components 202, 204 (FIG. 8B) are first movedoutwardly, for example a travel of about 12 mm, with a lower moldcomponent 116 then being moved downwardly (FIG. 8C), for example atravel of about 160 mm, the side mold component 102 and molded componentmoving outwardly (FIG. 8D) from mold component 112, for example a travelof about 400 mm, the mold component 102 moving away from the moldedcomponent (FIG. 8E), for example a travel of about 60 mm, and the moldedcomponent moving downwardly from the upper mold component 114 (FIG. 8F)and being ejected, whether manually mechanically or by pneumatically bypressurized air.

During the cross-steaming and autoclave steps, the method includesintroducing steam 160 into the mold interior 106 through the pluralityof vents 82 for a predetermined period of time. In response to theintroduction of the steam, the method further includes fusing the beads150 of polypropylene foam together with the steam and thereby formingthe molded element 68.

In one embodiment, the mold includes at least a pair of opposingtextured molding surfaces 104, 118 defining at least in part the moldinterior 106 therebetween. In another embodiment, the mold furtherincludes at least an upper and lower textured molding surfaces 114, 116further defining the mold interior 106, and also end textured moldingsurfaces.

The molded element 68 may be configured as a partition wall, or as anyother molded EPP component. The molded component may include anin-molded component, such as an accessory interface 90, handle or othermember. The in-molded component is positioned in the mold interior, withthe EPP foam beads flowing around the in-molded component, and expandingthereagainst.

Although the present invention has been described with reference topreferred embodiments, those skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. As such, it is intended that the foregoingdetailed description be regarded as illustrative rather than limitingand that it is the appended claims, including all equivalents thereof,which are intended to define the scope of the invention.

What is claimed is:
 1. A mold for molding particle foam comprising: amold component defining at least a part of a mold interior, wherein themold component comprises at least one class-A textured molding surfacehaving a roughness depth of less than or equal to 1.0 mm and a pluralityof vents having a maximum width of less than or equal to 0.4 mm.
 2. Themold of claim 1, wherein the plurality of vents are distributed with adensity of one vent per 100 mm² of surface area or less.
 3. The mold ofclaim 1, wherein the mold interior is further defined by an upper andlower textured molding surface.
 4. The mold of claim 1, wherein the moldinterior has a volume of less than or equal to 1800 mm×1240 mm×100 mm.5. The mold of claim 1, wherein the mold interior defines an exteriorshape of a partition wall.
 6. The mold of claim 1, wherein the roughnessdepth is less than or equal to 0.4 mm.
 7. The mold of claim 1, whereinthe vents have a circular cross-section with a diameter of less than orequal to 0.4 mm.
 8. A mold for molding particle foam comprising: a moldcomponent defining at least a part of a mold interior, wherein the moldcomponent comprises at least one class-A textured molding surface havinga plurality of vents having a maximum width of less than or equal to 0.4mm and distributed with a density of at least one vent per 100 mm² ofsurface area or less.
 9. The mold of claim 8, wherein the moldingsurface includes three vent interfaces per 100 mm² of surface area orless.
 10. The mold of claim 8, wherein the molding surface has aroughness depth of less than or equal to 1.0 mm.
 11. The mold of claim8, wherein the mold component is a first side mold component and themold interior is further defined by a second side mold component. 12.The mold of claim 11, wherein the second side mold component includes aclass-A textured molding surface having a roughness depth of less thanor equal to 1.0 mm and a plurality of vents having a maximum width ofless than or equal to 0.4 mm.
 13. The mold of claim 8, wherein the ventsare randomly placed.
 14. A mold for molding particle foam comprising: afirst side mold component at least partially defining a mold interior; asecond side mold component further defining the mold interior; an uppermold component further defining the mold interior; and a lower moldcomponent further defining the mold interior, wherein at least one ofthe mold components comprises a class-A textured molding surface havinga roughness depth of less than or equal to 1.0 mm and a plurality ofvents having a maximum width of less than or equal to 0.4 mm.
 15. Themold of claim 14, wherein one of the mold components is moveable by anactuator.
 16. The mold of claim 14, wherein one of the upper and lowermold components includes a stepped configuration for forming a wallelement having a channel.
 17. The mold of claim 14, wherein theplurality of vents are distributed with a density of one vent per 100mm² of surface area or less.
 18. The mold of claim 18, wherein the ventsare configured in an array.
 19. The mold of claim 14, further comprisinga supply line in communication with the mold interior and a steam supplyin communication with at least one of the mold components.
 20. The moldof claim 14, further comprising a first end mold component and a secondend mold component further defining the mold interior.